Most countries use Celsius as a unit of measurement for calculating the temperature. Many online applications will precisely convert Celsius into Fahrenheit but if you don’t have access to the Internet, use the following techniques to give you a good estimate.

Steps

Method1

Estimating an Approximate Temperature

1

Determine the temperature. Look for a temperature display. Many public clocks display the temperature below the time. Ask someone to tell you the temperature if you cannot locate a thermometer or temperature display.

2

Multiply the temperature by 2. Use a calculator or simply multiply the numbers in your head. Either way, you want to double this number.

3

Add 30 to this number. Take the doubled number and add 30 to it. Make use of a calculator or perform the addition in your head. This will give you an approximate temperature in Fahrenheit.[1] For example:

Determine the temperature in Celsius: 20 degrees

Multiply this number by two: 20 x 2 = 40

Add thirty to this number: 40 + 30 = 70 degrees Fahrenheit

Method2

Estimating a Semi-Precise Temperature

1

Determine the temperature. Find a temperature display. Look for a public clock on a building such as a bank. Many public clocks also display the temperature below the time. Ask someone to tell you the temperature if you cannot locate a thermometer or temperature display.

2

Multiply the temperature by 2. Use a calculator or simply multiply the numbers in your head. Either way, you want to double this number.

3

Subtract 10% from this number. Calculate 10% by multiplying the number by 0.1. For example, 100 x 0.1. = 10. Subtract this number from the number you doubled in the first calculation. Use a calculator to perform these operations for best results.

4

Add 32 to this number. Take the doubled number and add 32 to it. Make use of a calculator or perform the addition in your head. This will give you a semi-precise temperature in Fahrenheit.[2] For example:

Determine the temperature in Celsius: 20 degrees

Multiply this number by two: 20 x 2 = 40

Determine ten percent of this number: 40 x 0.1 = 4

Subtract this number from your number in step two: 40 – 4 = 36

Add thirty-two to this number: 36 + 32 = 68 degrees Fahrenheit

Method3

Memorizing Key Numbers

1

Learn rough comparable temperatures by heart. These numbers are easy to memorize and will allow you to make quick conversions.[3] Memorize Celsius to Fahrenheit using multiples of 10:

0 degrees Celsius equals 32 degrees Fahrenheit.

10 degrees Celsius equals 50 degrees Fahrenheit.

20 degrees Celsius equals 68 degrees Fahrenheit.

30 degrees Celsius equals 86 degrees Fahrenheit.

40 degrees Celsius equals 104 degrees Fahrenheit.

2

Learn comparable temperatures by heart. These numbers are fairly easy to memorize and will allow you to make precise conversions.[4]Memorize Celsius to Fahrenheit using multiples of 5:

To estimate a Celsius temperature in Fahrenheit, multiply the temperature by 2, then add 30 to that number. This will give you an approximate temperature in Fahrenheit. If you need a more precise estimate, multiply the temperature by 2, then subtract 10% and add 32 to that number. The result will more closely represent the Celsius to Fahrenheit conversion. For help memorizing a few Celsius to Fahrenheit conversions, keep reading!

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